2021521 has 4 divisors (see below), whose sum is σ = 2140452. Its totient is φ = 1902592.

The previous prime is 2021519. The next prime is 2021527. The reversal of 2021521 is 1251202.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 731025 + 1290496 = 855^2 + 1136^2 .

It is a cyclic number.

It is not a de Polignac number, because 2021521 - 2¹ = 2021519 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 8.

It is not an unprimeable number, because it can be changed into a prime (2021527) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 59440 + ... + 59473.

It is an arithmetic number, because the mean of its divisors is an integer number (535113).

2^2021521 is an apocalyptic number.

It is an amenable number.

2021521 is a deficient number, since it is larger than the sum of its proper divisors (118931).

2021521 is a wasteful number, since it uses less digits than its factorization.

2021521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 118930.

The product of its (nonzero) digits is 40, while the sum is 13.

The square root of 2021521 is about 1421.8020255999. The cubic root of 2021521 is about 126.4424063570.

Adding to 2021521 its reverse (1251202), we get a palindrome (3272723).

The spelling of 2021521 in words is "two million, twenty-one thousand, five hundred twenty-one".